Tuesday, March 27, 2012

2881.txt

date: Wed Oct 14 13:51:06 2009
from: Tom Melvin <t.m.melvinatXYZxyz.ac.uk>
subject: Finland Conference
to: Keith

Keith,

By June we are unlikely to have the long Eurasian paper ready to discuss.
Would it be better for you to present on Divergence e.g.

CHALLENGES POSED BY DIVERGENCE

1. Problem with curve-fitting e.g. Hugershoff (Briffa 1998) and trend distortion - part solution Signal free.

2. Problem with mixing sloping and horizontal curve fitting in Arstan (e.g. D'Arrigo 2004) - part solution RCS.

3. End effect problems with RCS (Briffa - Hughes book) - e.g. sample bias

4. Problem with updating chronologies (TTHH and Grudd 2008, Tornetrask)

5. Potential problem with Crown dieback (e.g. responders / non responders)

6. Potential MXD in sapwood problem ????

7. Potential competition problem - tree density changes RCS shape (Helama 2006)

8. Problem with non-linear response / skewed index distribution (Barber, Wilmking etc)

9. Remove all these and residual is real divergence - problem with identifying cause:
CO2 change / Nitrogen fertilisation / Global dimming / UV light / Drought stress/

Conclusion - Lots of work to do to clarify situation.

I would present on PBS//GUESS work.

We need to prepare abstracts in next week or so.

Tom

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